| 摘要 |
<p>A method of casting or moulding an article (1) having a screw-threaded hole in a mould cavity (7) is characterized by introducing casting or moulding material into the cavity (7) around a core pin (9) formed with segments (10) of a screw thread separated by flutes (11) and around withdrawable flat core members (12) which project into the cavity with their leading ends fitting snugly into the flutes, the screw-threaded segments forming a male image of the female screw thread (4) to be formed in the article allowing the casting or moulding material to set, withdrawing the core members (12) from the mould cavity (7), rotating the core pin (7) to bring the screw-threaded segments (10) to the position formerly occupied by the flutes (11), withdrawing axially the core pin from the cavity (7) and removing the article from the cavity (7).</p><p>The method facilitates the formation of an internally screw-threaded article which uses the minimum of material for its strength.</p> |
